A latch-up is a type of short circuit that can occur in a metal-oxide semiconductor field-effect transistor (MOSFET) circuit, such as complementary metal-oxide semiconductor (CMOS) circuits in an integrated circuit (IC). More specifically, a latch-up is the unintentional creation of a low-impedance path between the power supply rails of a MOSFET circuit. This inadvertent low-impedance path activates a parasitic structure, which disrupts proper functioning of the circuit and causes overcurrent that can potentially destroy the circuit. Power cycling the MOSFET circuit may correct the latch-up in some cases, while in other cases, proper functioning of the circuit may be unrecoverable (e.g., if the latch-up is not removed in time and the circuit is permanently damaged).
One type of latch-up is known as a single event latch-up (SEL), which is typically caused by radiation, for example, of heavy ions or protons from cosmic rays or solar flares. SEL can be extremely hazardous to electronics in space, causing permanent damage to ICs in a short amount of time due to the high currents involved. The risk of SEL prevents many contemporary commercial ICs—including field-programmable gate arrays (FPGAs), complex programmable logic devices (CPLDs), other types of programmable ICs, application-specific integrated circuits (ASICs), and system-on-chips (SoCs)—from being employed in aerospace, deep space, and earth orbiting applications (e.g., in satellites and spacecraft).